Purification of the Boston Water-Supply.—The water with which the city of Boston is supplied became affected last October by a peculiar and disagreeable taste and odor which made it unpalatable, and justified much complaint on the part of citizens. The taste was quite accurately described as a "cucumber-taste," from its resemblance to the taste of water which has stood in contact with cucumbers. In a milder form it was called a "fish-oil taste." After several efforts to determine its origin, Professor Ira Remsen, of Baltimore, was called in to give the subject a thorough examination. He, after patient investigation and experiments, which failed to discover the cause of the odor in other matters, determined its source, by the most satisfactory tests, to be the decomposition of a fresh-water sponge (Spongilla fluviatilis), that was found quite abundantly in the mud of the bottom of Farm Pond, the water of which was most offensive. Measures have been taken to free the pond from the cause of impurity.

The Hessian Fly.—From a monograph published by Professor A. S. Packard, Jr., through the United States Entomological Commission, it appears that the losses from the Hessian fly are greatest in the grain-raising areas of the Middle and Northwestern States and the adjoining regions of Canada, while the New England States have been comparatively free from its attacks, probably because so little wheat is cultivated in them. No statistics as to the losses have ever been collected, but they have been sufficient to occasion much consternation and alarm in certain years. Two broods of the fly are produced in a year, the first laying its eggs in April and May, the second in August and September. The dam age is done by the larva, which lies at the sheathing base of the leaves first above the roots, at or near the surface of the soil, and absorbs the sap from the stalks. From the larva, the insect passes into the pupa state, in which it resembles a flaxseed, and remains in it for the five winter months. The pest flourishes best in rather warm and moist seasons; and it has been noticed that the years when it has been most abundant have been characterized by weather answering to that description. It is afflicted by several parasites by which it is said that nine tenths of every generation of the insects are destroyed. The principal parasites are a chalcid fly that destroys the pupa, and a platygaster, which lays its eggs in the egg. Professor Packard recommends, as remedies for the insect, late sowing of fall wheat, so that the flies may be killed by frost before laying their eggs, high culture to give the plant new vigor, the sowing of the most vigorous and many-stooled varieties, and pasturing, which destroys the "flaxseeds," but is "a rather rude, uncertain remedy." Special remedies like limeing, dusting, burning stubble, etc., are not recommended, because they are inferior to those just mentioned, and are as likely to destroy the helpful parasites as the harmful flies. A comparison of the periods when the flies have been most abundant indicates that the plague has culminating periods in the neighborhood of twenty-five years apart.

Folk-Lore of the Mammoth.—Baron Nordenskiöld, in his "Voyage of the Vega," gives some interesting citations of the folk-lore of the Siberian natives respecting the mammoth, whose remains are very abundant in the country. Evert Yssbrants Ides, a Russian ambassador in 1692, related that the heathen Yakuts, Tunguses, and Ostiaks, supposed that the mammoth always lived in. the earth and went about in it, however hard the ground might be frozen, and that it died when it came so far up that it saw or smelled the air. J. B. Müller, in 1720, added that the tusks were believed to have formed the animal's horns, that they were fastened above the eyes and were movable, and that with them the animal dug a way for itself through the mud; when it came to a sandy soil, the sand ran together so that the mammoth stuck fast and perished. Müller further stated that many natives assured him that they themselves had seen such animals in large grottoes in the Ural Mountains. Klaproth says that the Chinese at Kiakhta considered mammoth ivory the tusks of the giant rat, tien-shu, which is found only in the cold regions along the coast of the Polar Sea, avoids the light, and lives in dark holes in the interior of the earth. Some of the literati believed that the discovery of these immense earth-rats might even explain the origin of earth-quakes. The horns and crania of the rhinoceros, which were found along with the remains of the mammoth, were believed to have belonged to gigantic birds, concerning which stories were related analogous to those told of the roc in the "Arabian Nights." Pieces of the horns were used to increase the elasticity of bows, and were believed to exert a beneficial effect on the arrow, and to tend to make it hit the mark. Ermann and Middledorf suppose that the finds of these remains two thousand years ago gave occasion to Herodotus's account of the Arimaspi and the gold-guarding dragons. Certain it is that during the middle ages such "grip-claws" were preserved as of great value in the treasuries and art collections of the time, and that they gave rise to many a romantic story in the folk-lore, both of the West and the East. Even in our own century, Hedenstrom, in 1830, otherwise an intelligent traveler, believed that the fossil rhinoceros-horns were actual "grip-claws."

Water-Temperatures at the Top and Bottom of Lakes.—Professor William Ripley Nichols has obtained, from the examination of the relative temperatures of the surface and the depths of fresh-water ponds near Boston, Massachusetts, results that differ from the views on this subject that are commonly held and taught. In Fresh Pond and Mystic Pond considerable difference was shown to exist in the temperature at the top and at the bottom, and the temperature appeared to decrease regularly from top to bottom. Having compared his own observations with those made in Swiss and Scotch lakes, in winter as well as in summer, Professor Nichols is led to the conclusion that "the water of lakes and ponds is, as a rule, before freezing, cooled to a temperature much lower than 4° Cent. (39° Fahr.), not simply at the surface, as generally stated, but to a considerable depth. The commonly received idea and the current statements of the text-books of chemistry and physics, are, therefore, misleading." The temperature of the water at the bottom of deep lakes is, moreover, not constant at the point of greatest density, as is frequently stated, but often lies appreciably above that point. Professor Nichols is not satisfied that we know sufficiently well the depth to which the diurnal variations of temperature extend under different circumstances. The curves of temperature in Mystic Pond show that there were several times when a few successive days of warm or cold weather produced an effect on the water, even at a depth of seventy-five feet. The paper recording these observations is supplemented by a list of other publications and papers bearing on the subject.

Sanitary Reports of British Schools.—The "Lancet" about a year ago addressed a series of questions to the managers of English schools respecting their sanitary provisions and the health of their pupils. The answers which it has received indicate that the subject is given considerably more attention than it was a few years ago, and that many of the managers sympathize with the editor in the object of his inquiries—that of ascertaining the conditions of the best scholar-health. The first report made by the journal summarizes the replies received from thirty-nine schools, in relation to the points of the character of the situation and buildings, and the climatic conditions; the amount of air-space per pupil in the sleeping and school-rooms; general state of health, cases of illness; sanitary arrangements as regards drainage, closets, lavatories, bathing, towels, etc.; provisions for the isolation of contagious cases; and provisions for medical inspection. No particular relation seems to be shown between the presumed healthful or unhealthful character of the site, and the presence or absence of disease. The sleeping-rooms afford from 273 to 1,300 cubic feet of air per individual; if the schools were full, the probable average allotment would be between 300 and 400 feet. The provision of air in the school-rooms is "fairly ample." The drainage is pronounced good in nearly every school, and no cases of illness are mentioned which could be traced to defective drainage. Lavatory arrangements are well attended to, with provisions for hot, cold, and swimming baths, and separate towels, brushes, etc., for each boy. Eight schools report that no cases of illness occurred during the year, one never having occasion to send for the doctor. The diseases mentioned include ophthalmia in two schools, pneumonia in two, "congestion of the lungs" in two, peritonitis in one, rheumatic fever and erythema nodosum in one, and sore-throat in one. Measles occurred in fifteen schools (fifteen cases in one), scarlet fever in twelve (fourteen cases with one death in one school), varicella in two, mumps in three (thirty cases in one school), Rotheln in three, whooping-cough in two, and typhoid fever in one. Many of the schools have provision of some kind for the isolation of pupils sick with contagious disease. Only five schools have arrangements for systematic medical inspection. The value of these returns is modified by the fact that the schools having the best sanitary arrangements and showing the best condition would naturally be the ones most ready to report.

Recent Existence of the Mastodon.—Professor Collett's "Geological Report of Indiana for 1880" mentions some new facts that seem to indicate that the mastodon existed in our country at a more recent date than is commonly supposed. In nearly all the specimens that have been found, generally in places where the animal has been mired, the skeletons are in a greater or less state of decay. In a skeleton discovered a few years ago, in Fountain County, the marrow of the larger bones was used by the workmen to grease their boots, and the place of the kidney-fat was occupied by lumps of adipocere. During the summer of 1880 a mastodon was found in Iroquois County, Illinois, that gave every evidence of having lived among the same life and vegetation as prevail to day. A mass of fibrous, bark-like material was found between the ribs, filling the place of the animal's stomach, which proved to be composed of crushed herbs and grasses, similar to those that still grow in the vicinity. In the same beds of miry clay, a multitude of small fresh-water and land shells were observed and collected, of mollusks which prevail all over the States of Illinois, Indiana, and parts of Michigan. These facts afford strong evidence that animal and vegetable life, and consequently climate, are the same now as when the mastodon lived.

Some Rare Meats.—The flesh of the elephant is relished by the inhabitants of many districts of Africa and Asia. Major Denham says that it is esteemed by all, and that, though it looks coarse, it is better flavored than the beef of the country. Gordon Cumming speaks of the dainty dishes of baked elephant's feet and elephant's trunk, which, prepared after a way he describes at length very much resemble buffalo's tongue. Le Vaillant says that baked elephant's foot is a dish fit for a king; but Captain Lindley likens it to "very soft leather and glue mixed together." Hippopotamus-meat is appreciated in Africa by both natives and European colonists, but Dr. Schweinfurth and Captain Lindley do not find it so appetizing. The fat of this animal and of the rhinoceros is considered delicious, and is used instead of butter. The Portuguese settlers are permitted to eat the flesh of these animals during Lent, passing it off as fish. The flesh of the American tapir, somewhat resembling unsavory, coarse, and dry beef, is considered palatable by the Indians and the fatty protuberance on the nape of it's neck and the feet and groin cooked to a jelly, are regarded as great delicacies. The horse is said to have been universally used as food before the period of civilization, and was greatly liked by the ancient Germans and Scandinavians. Mungo Park speaks of wild horses being eaten in Africa. Mare's flesh is a choice morsel to the Chilian Indians. The efforts to reintroduce horse-flesh as food had considerable success in some European capitals. The Greeks ate donkeys; the flesh of the wild ass is held in high esteem by the Persians and Tartars; and the quagga and zebra form favorite dishes among the Hottentots and in Central Africa. Camel's flesh is highly esteemed in Africa, but is not liked by the Tartars. The hump, however, cut in slices and soaked in tea, serves the purpose of butter. The South American alpaca affords a flesh little inferior to mutton. The flesh of the young giraffe is very delicate, and the marrow is held at a high value. Passing the animals of the deer and bovine tribes, which are appreciated by all, we come to the whales and seals. which furnish a chief part of the food-supply of the Esquimaux. The walrus is highly esteemed in the Arctic regions and its tongue, heart, and liver are often eaten by whalers in the lack of better provisions. The dolphin is eaten at the Faroe Islands, where two thousand individuals are taken annually. The flesh of the dugong is good and palatable, having the flavor of pork combined with the taste of veal, and is esteemed a great delicacy by the Mohammedan Malays, who find in it a substitute for the pork that is forbidden them. The meat of the young animal salted and cured, with the flesh and fat in its alternate layers, produces a bacon which can not be distinguished from that of real pig, and which finds a ready sale in Queensland. The oil, properly dried out, is equal to fresh butter.

Suggestions to Observers in Anthropology.—Recognizing that the rapid advance of civilization is causing the native races everywhere to disappear, or is modifying them essentially, and that what still exists in its originality must be saved now, the Anthropological Society of Hamburg has framed a schedule of questions, to be sent out to persons who are in a position to answer them intelligently, respecting the more important characteristics of the aborigines of the several countries. The questions concern—first, the names of tribes and the districts in which they live; the color of the tribes, the characteristics of their hair, the material and fashion of their clothing, the ornaments—of whatever kind—they wear, and how they wear them, the marks of paint, cutting, and tattooing, that they put on their skin whether they file or knock out their teeth; their weapons, how they make them and how they use them, and their defenses; the material, architecture, furnishing, and adornment of their dwellings, whether they be huts, pile-dwellings, caves, or tents; their public buildings, temples, sacred places, and altars; their domestic, hunting, and farming utensils, pottery, glassware, metallic and wooden vessels; how they make and apply their paints; their mining arts; their usages in trade; their money and their manner of counting; how they make their fires; their intoxicants and narcotics; what they know and have of music and musical instruments; what with them takes the place of writing; their superstitions and folklore, and particularly the objects to which they give special honors; their social customs and usages in intercourse with friends and enemies; observances in the matters of birth, marriage, and death; their diseases and methods of cure; their ideas as to a future state; their traditions as to their origin; their knowledge of the stars, and their manner of computing time. The questions covering these points in detail are to be sent out, in English and German, to ship-captains, merchants, consuls, and missionaries, who, it is expected, will enter upon the schedule notes embodying such information as they can furnish. As it is impossible to make the questions exhaustive, further communications than those asked for, such as the judgment of the respondent may dictate, will be thankfully received.

An Artificial Volcano.—The newspapers of Cologne tell of a kind of artificial volcano which was produced recently at Apenrade, in the Rhine provinces, in the course of the digging of an artesian well. At the depth of not quite five hundred feet, a strong ebullition was noticed, accompanied by a dull rumbling. Then, all at once, the earth and stones in the tube were violently blown out to a considerable height, with a heavy detonation, and a column of gas came up hissing. When lighted with a match, the gas burned with a clear flame, rising high in the air, till it was extinguished by a new eruption of pebbles and dirt. Eruptions of stones and gas continued till the time the story was told, when the flame of the gas continued to be of undiminished intensity. The phenomenon was occasioned, of course, by one of those accumulations of gas which I take place now and then in the bowels of the earth, giving rise to fire-damp explosions in coal-mines, causing earthquake-shocks in countries which are not volcanic, and giving rise to the so-called "mud-volcanoes," when the gas forces its passage through beds of moist clay.

Origin of Native Gold.—Professor J. S. Newberry has presented some strong points of fact and argument against the theory that the grains and nuggets of gold found in placers are formed by precipitation from chemical solutions. He holds, in a paper he has published on the subject, that geology teaches, in regard to the genesis and distribution of gold, that it exists in the oldest known rocks, and has been thence distributed through all strata derived from them; that, in the metamorphosis of these derived rocks, it has been concentrated into segregated quartz-veins by some process not yet understood; that it is a constituent of fissure-veins of all geological ages, where it has been deposited from hot chemical solutions, which have reached deeply buried rocks of various kinds, gathering from them gold with other metallic minerals; and that gold has been accumulated through mechanical agents in placer deposits by the erosion of strata containing auriferous veins.

What has been gained by Vivisection.—Dr. Ferrier was recently arrested in England for practicing vivisection without a license, and the members of the British Medical Association were indignant at the act, regarding it as an insult and a measure of annoyance. Dr. Ferrier's offense seems to have been observing with Dr. Yeo, who had a license, experiments that were intended to throw light upon certain features of the treatment of lesions of the brain. Dr. Ferrier's investigations in this department, which would have been impossible without vivisection, have been of immediate and of the greatest value to mankind. Among the results of them has been the discovery of the means of localizing in its definite region the point where an injury, resulting in epileptic fits, has been inflicted, and of applying remedial treatment to the precise spot where it will be effective. Dr. Echeverria has given a list of 165 cases of traumatic epilepsy, 64 per cent of which were cured by trephining. Before Dr. Ferrier's experiments this trephining would have had to be done blindly. The knowledge gained by Dr. Ferrier's researches has also been useful in guiding to the spot where pus has accumulated in case of abscesses in the brain, and in indicating the site of tumors. Considering how recently these discoveries have been made, it in fact seems extraordinary that they should have been already productive of so much benefit. The operations on the animals are not painful after the exposure of the brain has been accomplished, and that is done under anæsthetics, nor does any pain follow the recovery from anaesthetic influence. The effects of the after-stimulations are simply the excitement of the wonder and curiosity of the animals at their involuntary motions. Probably a single sportsman inflicts more pain in a day's shooting than Dr. Ferrier has done in the whole course of his researches.

A New Natural Hydrocarbon.—Professor Henry Carvill Lewis has published a description of a new substance resembling dopplerite which has been found in a peat-bog at Scranton, Pennsylvania. It is black, jelly-like in consistency, and elastic to the touch when first taken from the ground, breaking with a conchoidal fracture, but becomes tougher and more elastic, like India-rubber, immediately on exposure to the air. Occasional seeds, having the characters of the spores of one of the higher cryptogams, occur in the substance, as well as in the surrounding peaty matter. The composition of the substance nearly corresponds with the formula C10H22O16, differing from that of dopplerite in the presence of much larger proportions of hydrogen and oxygen. Professor Lewis suggests that this product is, perhaps, an intermediate product between peat and coal, and proposes to combine it with dopplerite under the generic name of phytocollite ("plant-jelly").

Parasites.—Professor Arnold Heller, of Kiel, has recently published an interesting work on parasites, with particular reference to their import to men. It is only lately that the true origin and character of parasites have been at all adequately understood. Not very long ago they were supposed to be formed out of the substances of the body; and in the condition of knowledge at the time it was hard to account otherwise for their presence in certain parts of the system. They have also been supposed to be received by inheritance; and it has not been fully proved that, in rare instances, this may not be the case. It has, however, been shown that, as a rule, they are introduced into the system, either directly or through germs taken in with the food, breathed in the air, brought by unclean hands or with unclean dishes, or blown in with the dust. They are generally dependent on moisture for their vitality, and, finding in the bodily juices a favorable environment, may become suddenly active after having been long dormant in uncongenial situations. Most, if not all of them, probably existed originally in a free state, and have become wonted to what is now an exclusive abode by gradual adaptation in long time; in such cases, they seem to have lost some of the organs, such as those of locomotion, which they originally possessed, but which have become of no further use to them. Some of them have been made useful to man. The leech serves a valuable purpose in the healing art; the cochineal aphis furnishes a valuable dye; the tape-worm of the snipe tickles the palate of the hunter and the epicure as "maccaroni-piatti"—flat maccaroni; and the worms of fresh-water fishes are esteemed as food in some parts of Italy. The ichneumon flies and their tribe are of inestimable benefit in destroying the insect enemies to vegetation; and helpful moths have been discovered which prey upon the moths and other insects in the furs of rodents and the feathers of birds. Among vegetable parasites, ergot is valuable in medicine, and the mistletoe-berry is used in making bird-lime and fly-paste. It has been suggested that even intestinal worms may be good for children by helping to consume the excess of slime; and Jordan, of Mayence, has set forth that the animals that infest the skin of man may be beneficial by forcing him to look after the cleanliness of his person and clothing, and his intestinal worms by making him careful of his food. This view can not, however, be justified, even when we admit that parasites in many cases do no perceptible harm. To these cases may be opposed the numerous instances in which they have proved destructive to their hosts, whether animals, birds, or men, often carrying off multitudes of creatures when they become excessively abundant on a species; and in the most favorable cases they give the host discomfort and inconvenience, though their work maybe overlooked in the presence of his superior vigor. As a rule, parasites belong to the lower orders of animals—worms or insects. Sometimes an arachnoid or a crustacean will join the company; but a few small fishes are the only creatures among the vertebrates that ever assume that relation. The stories that have been told of the existence of other inhabitants in the system are either fables or have originated in the accidental presence of single individuals who were probably as much astonished as their host at finding themselves in such a home.

The Repeating Melograph.—M. J. Carpentier exhibited, at the recent electrical exhibition in Paris, an instrument called the repeating melograph, by means of which, he claimed, any piece or improvisation which a composer may play on the key-board to which it is attached is registered, and may be repeated upon any other instrument with which it may be connected. It, more-over, secures the repetition, not of the piece only, but of the style, even to the false notes, of the player. Both processes, the registering and the repeating of the piece, are performed through the medium of electric currents. In the former case the keys of the instrument on which the piece is played are connected with wires through which a current is established when the key is pressed down. This current sets in operation an apparatus, with tools answering to the several keys, by means of which a perforation corresponding in character with the musical value of the note is made in a moving band of paper. The piece being finished, the band is ready to serve in a second execution of it. Electric communication is effected between the perforated band and the second instrument; and a current is formed, causing a corresponding key to be sounded at each perforation of the band as it passes the circuit in the process of unrolling. M. Carpentier contemplates adjusting his instrument so that it may also be made to print the piece in ordinary musical type.

Electric Units.—The International Congress of Electricians at Paris unanimously agreed upon a uniform standard of electrical units of measurements. It decided to adopt the fundamental units, the centimetre, the gramme, the second (C. G. S.); that the practical units, the ohm and the volt, should be defined, as now, the ohm as 109, and the volt as 108; that the unit of resistance (ohm) be represented by a column of mercury having a section of a square millimetre at the freezing-point, and a height to be determined experimentally by the International Committee; that the current produced by a volt in an ohm be called an ampere instead of a weber, the latter name having been applied by Weber himself in Germany to a current of ten times less force; that the name of coulomb be applied to the quantity of electricity defined by the condition that an ampère gives a coulomb a second, the former English weber; and that the name farad be applied to the capacity defined by the condition that a coulomb in a farad gives a volt—which is equivalent to the farad of the British Association. The Carcel lamp was recommended to be continued as the standard for the comparison of lights, pending the investigations of an International Committee to ascertain and fix upon the most practicable standard.

"Clouds of Seeds."—A correspondent of "La Nature" describes a remarkable appearance of seeds in the air that was observed in Guatemala during eight consecutive days in February last. In the early hours of the afternoon it was easy to perceive at a certain distance from the ground bodies resembling snow-flakes, which appeared and disappeared instantaneously, generally going in the same direction, but which were visible only when they passed between the sun and the observer. They moved gracefully, with variegated colors, falling and then rising out of sight, as snow-flakes do when they melt in the air; at other times they were carried along by the wind. The populace thought that fire was falling from the sun. More intelligent persons believed that snow had been actually formed in consequence of the cooling of the atmosphere, some of which had fallen without melting till it came in sight, and this view was currently accepted. It was finally shown; however, that the particles were floating seeds, and every one was enabled to satisfy himself of the fact by grasping a handful of them.